To the Editor.—Beede and colleagues1 state that their data on the positive— predictive value of the clinical assessment of abdominal aortic aneurysms (AAAs) "indicate that screening for AAAs in routine clinical practice based on clinical assessment of AAAs may be much less cost-effective than proposed" by us2 and by others.3 This statement can be challenged on several grounds.

First, because of the retrospective nature of the study, there could be no specific criteria for a "clinical assessment" of AAA. The authors note that normal aortic pulsation in thin persons was probably a frequent reason for ultrasound. In contrast, our study2 confirmed the dictum of Osler4 that only an enlarged aortic pulsation should be considered clinical evidence of AAA. The positive-predictive value of an ill-defined clinical assessment should not be compared with the positive-predictive value that we reported for a pulsatile mass. Referral based on